Most systems, which are of actual scientific interest, are complex. Some of them are non-linear, thus those systems exhibit dynamical chaos – minor error in initial conditions causes system evolution, which was not predicted. Typical example of such unpredictability is found in weather forecast – due to Butterfly effect even modern supercomputers can give credible week-long predictions of weather. But there is set of non-linear systems within which even minor impact from outside, or let it be error in initial conditions, can cause major and momentary change in observed behavior. Typical example of this kind of system might be financial markets.
It is convenient, in case of sensitive systems, to assume those impacts to be random. In such case it is said that system has stochastic nature. Thus models of such system are called stochastic models. Those models are usually implemented using stochastic calculus, namely stochastic differential (usually Langevin) equations.
Within this section of Physics of Risk website we will demonstrate the power of stochastic calculus and possibilities of stochastic modeling.
Topic: “Modelling power-law distribution, 1/f noise and financial markets using stochastic differential equations”
Speaker: habil. dr. Bronislovas Kaulakys
When? 14th of May, 17:00.
Where? VU Faculty of Mathematics and Informatics (Naugarduko g. 24, Vilnius), 400 auditorium.
Organized by: Department of the Mathematical Analysis of the VU MIF.
Last time we have written on the power spectral density and we have “analyzed” deterministic periodic time series. This time we will consider spectral densities of some stochastic processes. Continue reading “Power spectral density (part 2)” »
The most active and well known scientists contributing towards FuturICT project have organized their ideas into few articles, which discuss the current situation in contemporary complex social system modeling. These articles we published in a special issue of “The European Physical Journal Special Topics”. Most of the articles are available for free, thus we invite you to familiarize yourselves with them.
Previously, approximately 2 years ago, we have written that we published a review of our works 1 in a book by open-access publisher. Recently we discovered that during the recent two and a half years this books was downloaded almost 7000 times (namely 8 times per day). It was downloaded by the people all around the world – with the USA, China, India, Japan, Germany being the most active countries in the process. It is an excellent result!
While being happy with excellent “diffusion” of our ideas via open-access publisher, we would also like to speak about the improving statistics of the Physics of Risk website. In 2012 we expect to be visited 12 thousand times! It is slightly better than in 2011, in which we had 11 thousand visits. Improvement is small, yet promising a bright future. Continue reading “Download rates of our open-access review” »
In October 2012 our group has familiarized themselves with this interesting theory. Few seminars, which were held at VU ITPA, on the stochastic theory of nonequilibrium steady states were read by dr. Julius Ruseckas, one the researchers in our group. This theory is discussed in two articles recently published in the Physical Reports journal 1, 2. Read on Continue reading “On the stochastic theory of nonequilibrium steady states” »
Topic: “Agent-based Versus Macroscopic Modeling of Competition and Business Processes in Economics and Finance”
Speaker: dr. Vygintas Gontis
Briefly: The talk will be focused on the agent-based and stochastic modelling done by the Department of the Theory of Processes and Structures of the VU ITPA.
When? 6th of November, 17:00.
Where? VU Faculty of Mathematics and Informatics (Naugarduko g. 24, Vilnius), 400 auditorium.
Organized by: Department of the Mathematical Analysis of the VU MIF.
Quantum mechanics and statistical physics use very similar and inter-connected concepts. Ex. the latter is concerned with distribution and probabilities, while the former operates with wave functions and amplitudes. Even the essential equations, master and Shrodinger, appear to be similar:
The only difference is the imaginary factor i! But these similarities lie just on the surface… Continue reading “Quantum mechanics + statistical physics = ?” »
Topic: “Physics is not a risk: Brief introduction into the Physics of Risk”
Speaker: Aleksejus Kononovičius
Briefly: Social sciences have accomplished many different things. Yet it should be evident that there is a place for improvements – to look into the old and new social problems a bit differently. As many of the social problems are strongly non-linear and very complex, the physicists’ point of view is very useful. This, new, point of view is known as Physics of Risk.
When? 18th of October, 17:00.
Where? VU Faculty of Physics (Saulėtekio al. 9, III rūmai, Vilnius), 201 auditorium.
Organized by: VU Faculty of Physics Students Scientific Association.
Facebook event: here.
Slides: download (in Lithuanian).
The simplest ecological system can be constructed from the two interacting species, ex. prey and predator. This kind of system is very interesting in the terms of Physics of Risk primarily because it is nonlinear 1, and due to being real life example of competition (conflict). Also there are few known simple models for the prey-predator interaction. Among them there are both macroscopic, Lotka-Volterra equations, and microscopic, agent-based, models. We will start our discussion from the macroscopic Lotka-Volterra model. Continue reading “Lotka-Volterra equations” »
What is white, pink, “brown” and even black? It is around us every day and usually is very useful. Yet from time to time it annoys us and sometimes we even call police to keep it in check? The answer to this quite complex, as it is oriented towards people with physics background, question is unbelievably simple. Noise possesses all of the aforementioned qualities! Continue reading “Colors of Noise” »
2006-2013 Vilnius University Institute of Theorethical Physics and Astronomy.
